As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: BRAKES PULSATING BELOW 60 KNOTS ON ROLLOUT. NO IRREGULAR INDICATIONS ON HYD PAGE OR INDICATOR LIGHTS. MAINTENANCE FOUND THE ALTERNATE BRAKE SERVO VALVE LEAKING AND REPLACED IT PER AMM 32-43-27. A SATISFACTORY LEAK / OPERATIONAL CHECK WAS ACCOMPLISHED.